Prime Minister Justin Trudeau has sought to reassure Canadians they will be protected when screened by US officials as part of expanded Canada-U.S. border preclearance.

Extra powers will be given to U.S. customs officials working on Canadian soil as part of a deal originally reached by former Prime Minister Stephen Harper and previous president Barack Obama.

But new President Donald Trump’s USA immigration crackdown has Canadians fearing the prospect of extreme vetting taking place at Canada-U.S. border preclearance centres.

The Canada-U.S. border deal is covered by Liberal Bill C-23, seen as a positive when it was introduced in June 2016 as it seeks to speed up the process of crossing the border in either direction.

Quick Facts: The Canada-US Border

Longest international border in world at 8,891km, 2,475km of which is with Alaska.

3 million Canadians travelled to the USA in February 2016, with 2 million moving in the other direction.

400,000 people and $2.4 billion in trade cross the border each day.

Canada and US are second and fourth largest countries in the world by area.

Canadian provinces and territories on border: Yukon, British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick.

US states on border: Alaska, Washington, Idaho, Montana, North Dakota, Minnesota, Michigan, Ohio, Pennsylvania, New York, Vermont, New Hampshire, Maine.

But attitudes have changed in light of Trump’s recent executive order banning immigration from seven Muslim-majority countries, with Canadians facing heightened scrutiny and invasive questioning when trying to cross the Canada-U.S. border.

Trudeau said recently: “When you’re doing preclearance in Canada, the Canadian Charter of Rights and Freedoms and Canadian laws are in place, so there is extra protection when Canadians go through American customs in Canada because they are protected by the Charter on Canadian soil.”

In December 2016, a bill that would expand U.S. border pre-clearance in Canada was adopted by the American Congress.